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C. LUTTROPP CALCULATING MACHINE May 29, 192s. 1,671,537

Filed Dec. 10, 192s 2 sheets-sheet 1 C. LUTTROPP CALCULATING MACHINE May 29, 1928. 1,671,537

Filed Dec. l0, 1926 2 Sheets-Sheet 2 Patented May 29, 1928.

UNITED STATES PATENT OFFICE.

OF ONE-HALF TO ANDERS LINDAHL, OF STOCKHOLM, SWEDEN.

'CALCULATING MACHINE.

Application filed December 10, 1926, Serial No.-153,898, and in Sweden November 8, 1925.

This invention relates to calculating machines of the type having a traveling carriage movable step by step in response to the depression of a key.

The object of this invention is to provide Simple and reliable means, whereby the carriage may be shifted in either direction and at the same time positively prevented from moving more than one step at each depression no matter how heavy the operation of the key may be.

The invention is characterized, chiefly, by the provision on the carriage of a longitudinal ratchet bar having two series of ratchet teeth, one for each direction of movement, lone feed dog and one stop dog being provided to cooperate with each of said series of teeth, each such pair of dogs bein carried by a separate slide movable towar and away from said ratchet bar under the control of a key while being prevented from moving in a direction parallel to said bar.

In the drawing one embodiment of the invention is illustrated. Fig. 1 is a front view of the carriage moving device according to the invention. Fig. 2 is a Side elevation of part of the calculating machine. Fig. 3 is a front view of certain parts of the device shown in Fig. 1 in the positionsaid parts occupy at the end of a movement of the ratchet bar to the left. Fig. 4 is a horipntal section taken along the line 4 4 in r2fhe invention is illustrated as applied to a calculating machine the key-board of which comprises ten digit keys.

In Fig. 2 the key-board is indicated at 1 and two keys thereof are shown by dotted lines at 2, 2. Those parts of the calculating machine not required for the understanding of this' invention are omitted from the drawinfr.

rblhe traveling carriage 3 is slidably mounted on stationary tracks 4,4, preferably by means of balls 5, 5. Attached to the lower portion of the carriage is a ratchet bar 6 having on its under side two series of oppositely directed ratchet teeth 7'-, 8, respectively.`

Pivoted to the ratchet bar 6 is a locking lever 9, adapted to engage slots 10 formed in a stationary locking bar 11. The spacing of the slots 10 corresponds to the spacing of the teeth of the ratchet bar 6 said last men- 1 2 to permit manual release thereof, if desired.

Situated below the ratchet bar 6 is a stationary guide-block 13 forming vertical guide-ways for two slides 14, 15. Each of said slides is provided with adepending arm 16, 17, respectively, pivoted to one arm of individual'bell crank levers of which that associated with the slide 14 is shown at 18 in Fig. 2. The other arm of said lever 18 is connected by a link 19 to one arm of a bell crank lever 21 mounted at 20 and having its other arm connected to a key 22, as shown in F1g.'2. There are, of course, two such conpections and keys, one for each of the slides The bell crank lever 18 is formed with an elongated slot 23 guided by the stationary pm 24. Said pin 24 also engages a corresponding slot in the lower portion of a link 25 having a pin 26 engaging a cam shaped portion 27 of the bell crank lever 18. The upper end of the link 25 is pivoted to one arm of a bell crank lever 28 carrying a bridge 30 in engagement with the locking lever 9. The other arm of the bell crank lever 28 is formed as a journal pin 31 engaging the bifurcated shorter arm of a bell crank lever 32 the longer arm of which is formed with a stop shoulder 33 to engage a tooth 34 on the main shaft 35 of the calculating machine.

Pivoted to the slide 14 by means of a pin 36, see also Fig. 3, is a feed dog 37 adapted to cooperate with the series of teeth 7 of the ratchet bar 6. A spring 38 attached to the rear end of the feed dog 37 tends to move said end downwardly. The slide 14 together with the side walls ofthe guide-block 13 and one end wall 39 thereofform a vertical guide-way for a stop dog 40 adapted to engage the series of teeth 8 of the ratchet bar 6. B means of a pin 41 attached to the stop (fog 40 which engages an elongated slot 42 in the feed dog 37 intermediate between its ends the stop dog 40 is pivotally connected to the feed dog 37 without interfering with the desired movement ofthe feed dog. The feed dog 37 is providedfvith a lateral projection 43 to engage the stop dog 40 in order to limit the movement ofthe feed dog towards the stop dog as caused by the spring 38.

The slide 15 and its associated parts are equivalent to those described above in connection with slide 14. The slide 15, thus, carries a feed dog 47 adapted to cooperate with the series of teeth 8 and a stop dog 50 adapted to cooperate with the series of teeth 7 of the ratchet bar 6.

The operation of the mechanism described is as follows:

Assuming it is intended to move the carriage to the left, the key 22 is depressed thereby causing the bell crank lever 18 to lift both the link 25 and the slide 14. The link 25 causes the bell crank lever 28 to turn on its pivot. As a result, the bridge 30 will lift the locking lever 9 out of engagement with the slots 10 of the locking bar 11, and the journal shaped end '31 of the lever 28 will 'at the same time move the lever 32 to bring its shoulder 33 into engagement with the tooth 34 thereby temporarily locking the mainshaft 35 against rotation. Prior to the above described movement the slide 14 was in the position shown in Fig. 1 in which the dogs 37 and 40were in released state. By means of the pin 36 the slide '14 in its upward movement moves the feed dog 37 upwardly while the spring38 maintains the feed dog in Contact with the stop dog 40. 'Ihe stop dog is caused by the pin 4I to also move upwardly with the slide. When the point of the feed dog 37 reaches the bottom of that space of the series of teeth 7 which is situated just above the dog any further parallel movement of the feed dog is pre-A vented and, during the continued upward movement of the slide 14, the feed dog is caused to turn on the pin 36 thereby causing the point 'of the feed dog to move the ratchet bar 6 to the left. As long as this movement continues the stop dog 4G continues its upward movement. The stop dog which was initially on a height below that of the feed dog, as shown in Fig. 1, will in the last ortion of the movement enter a space of t 1e series of teeth 8 and will be in full engagement therewith when the feed dog 37 has moved the ratchet bar a distance of one tooth-space to the left. The various parts will now be in the position shown in lpon the subsequent release of the key 22 the slide 14 will restore, Vto normal moving both of the dogs 37 and4() out of engagef ment with the rowsof teeth 7 and 8. At the same time the locking lever 9 will enter one of the slots 10 of the locking bar 11 to maintain the carriage in its displaced position. Furthermore, release of the main shaft 35 will be eected simultaneously.

If it is'desired to move the carriage to the right the key associated with slide 15 is depressed whereby the slide 15 with its associated parts will be operated similarly as described above. v

,As all of the dogs are normally out of engagement with the ratchet bar 6, as shown in Fig. 1, the carriage may be released by -ment of each of said slides.

2. In a calculating machine, a frame, a carriage movable on said frame, a ratchet bar on said carriage having two series of oppositely positioned teeth, stationary vguiding means, .slides in said guiding means movable towards and away from said ratchet bar, a feed dog pivoted to each of said slides, a stop dog movably connected to each of said feed dogs, they feed dog being adapted to cooperate with one of said series of teeth and the associated stop dog being adapted to cooperate with the other series of teeth and means to control said slides.

3. In a calculating machine, a frame, a carriage movable on said frame, a ratchet bar on said carriage having two series of oppositel directed teeth, two slides movable towar s and away from said ratchet bar, a feed dog' pivoted to each of said slides at its rear end so as to normally occupy an inclined position relatively to the ratchet bar, a stop dog on each slide, and means to control said slides.

4. In a calculating machine, a frame, a carriage movable on said frame, a ratchet bar on said carriage having two series of .oppositelypositioned teeth, two slides movable towards `and 4away from said ratchet bar, stationary guiding means for said slides, separate controlling means for said slides, a feed dog pivoted to each slide so `as to normally occupy an inclined position relatively to the ratchet bar. a stop dog on each slide controlled by said slide and said feed dog in conjunction in such a way as to cause the stop dog to engage the ratchet bar during the last portion ofl the operation of the feed dog.

5. In a calculating machine, a frame, a. carriage movable on said frame, a ratchet bar on said carriage having two series o o positely positioned teeth, two slides mova le towards and away from said ratchet bar, stationary guidin means for said slides, separate controlling means for said slides, a feed dog pivoted to each slide so as to normally occupy on inclined position feed dog to maintain its inclined position relativel to the ratchet bar, astop dog on until the feed dog comes into engagement each sli e controlled by said slide and said with the ratchet bar. 10 Afeed dog in conjunction in such a `way as In testimony whereof I have signed my 5 to cause the stop dog to engage the ratchet name. bar during the last portion of the operation of the :feed dog, 'and a spring acting on said CONRAD LUTTRGPP.4 

